Orally fed spray dried plasma modulated the immune response during respiratory challenges: A review.

Multiple stress events at weaning can impact intestinal barrier function and induce immune dysfunction; thus affecting piglet performance and health. Spray-dried plasma (SDP) is processed from blood and contains several functional components with biological activity independent of their nutritional value. Bovine or porcine spray-dried plasma is used in pig feed at weaning due to its well-known beneficial effects on postweaning performance and health. These positive effects of dietary SDP may be related to modulation of the inflammatory response by interacting with the intestine (GALT) to affect the systemic response. In recent studies, the effects of orally feeding bovine or porcine SDP have been demonstrated systemically in pigs challenged with porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza (SIV) and in rats injected with a bacterial toxin. In PRRSV challenged pigs, porcine SDP reduced (P < 0.05) interstitial pneumonia and viremia by d 28, which was likely modulated by increased pulmonary pro-inflammatory cytokines. In SIV challenged pigs, bovine SDP reduced (P < 0.05) lung lesions and improved gain. Porcine spray-dried plasma reduced (P < 0.05) leukocyte infiltation and pro-inflammatory cytokines in the lungs and increased (P < 0.05) anti-inflammatory cytokine in both the intestine and lungs in mice intra-nasally exposed to a bacterial toxin. Collectively, these findings indicate that orally fed bovine or porcine SDP impacts the systemic inflammatory response to improve performance and health. Therefore, addition of SDP to animal feed helps to maintain and support the immune system and growth performance when the animal is exposed to a variety of stress events. [ABSTRACT FROM AUTHOR]